Add 30/70 and 21/12
1st number: 30/70, 2nd number: 1 9/12
30/70 + 21/12 is 61/28.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 70 and 12 is 420
Next, find the equivalent fraction of both fractional numbers with denominator 420 - For the 1st fraction, since 70 × 6 = 420,
30/70 = 30 × 6/70 × 6 = 180/420 - Likewise, for the 2nd fraction, since 12 × 35 = 420,
21/12 = 21 × 35/12 × 35 = 735/420 - Add the two like fractions:
180/420 + 735/420 = 180 + 735/420 = 915/420 - 915/420 simplified gives 61/28
- So, 30/70 + 21/12 = 61/28
In mixed form: 25/28
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 60/70+21/12 30/70+42/12 30/70+21/24 90/70+21/12 30/70+63/12 30/70+21/36 30/70+21/60 30/70+21/84